Oil cooler



FIG. 1 is an oblique perspective view of an oil cooler embodying my new design;

FIG. 2 is a front elevation thereof, the rear elevation being identical;

FIG. 3 is a left side elevation thereof, the right side being identical;

FIG. 4 is a top plan view thereof; and

FIG. 5 is a bottom plan view thereof. 

The ornamental design for an oil cooler, as shown and described. 